Noise limitation design criteria reduce the efficiency and maximum size of wind turbines because the blade tip speed must be reduced to limit noise, thus reducing the turbine's performance capacity. A major component of wind turbine noise is trailing edge aerodynamic noise (Matthew F. Barone, “Survey of Techniques for Reduction of Wind Turbine Blade Trailing Edge Noise”, Sandia National Laboratories, SAND20011-5252, August 2011, page 8). Trailing edge noise can be reduced by trailing edge serrations, as illustrated in FIG. 5 herein, which reduce the abruptness of the acoustic impedance mismatch between the merging suction side and pressure side flows at the trailing edge.
Vortex generators are mounted on the suction side of an airfoil to induce vortices that entrain kinetic energy from the bulk airflow into the boundary layer flow immediately against the suction side surface. Energizing of the boundary layer delays flow separation on the airfoil and allows higher angles of attack without stall, thus allowing a wider range of operating configurations and higher overall efficiency. However, vortex generators can add noise and drag in some conditions